In 2003, Jessi successfully auditioned for Doremi Media, and moved to South Korea at age 15. She released her debut single album, Get Up, in 2005, and performed the title song, “Get Up”, on the TV program Music Bank. In 2006, the hip hop group Uptown featured her in their album Testimony, replacing their original vocalist Yoon Mi-rae. Jessi’s second single album, entitled “The Rebirth”, was released in January 2009. After the release, she took a break from music, and left Korea to return to America.
In 2014, after a 5-year hiatus, Jessi returned as a member of hip-hop trio Lucky J with rapper J’Kyun and vocalist J-Yo. Lucky J debuted with the digital single “Can You Hear Me” under YMC Entertainment in July of that year. A month after their debut, Lucky J made an appearance in Mnet’s music competition program, Immortal Songs 2.
From January to March 2015, Jessi was part of the first season of Unpretty Rapstar, a spin-off of the program Show Me The Money. Unpretty Rapstar is a female rapper survival program, where contestants compete for the chance to be featured on tracks in a compilation album. Jessi was chosen as the second-place winner of the show by audience vote. After her appearance on Unpretty Rapstar, Jessi was featured in JYP’s single “Who’s Your Mama?” and its music video, which were both released in April 2015. The track topped all nine major music charts in Korea as soon as it was released. Throughout 2015, Jessi appeared as a guest in various popular variety shows, including Running Man and Happy Together. She released her first ever solo rap single, “Ssenunni”, on September 15. Jessi’s first live performance in the US was held on October 16. She performed at the Belasco Theater in Los Angeles with hip-hop duo Mighty Mouth as her opening act. When Unpretty Rapstar 2 aired, Jessi appeared in several episodes as a mentor. She and Cheetah, the winner of the previous season, were featured in Unpretty Rapstar 2 tracks produced by Verbal Jint. In December 2015, Jessi performed her song “Ssenunni” at the Mnet Asian Music Awards.
In 2016, Jessi starred as one of the permanent members in season 1 of popular Korean variety show, Sister’s Slam Dunk. In 2017, Jessi released another rap single, “Gucci” from her first mini-album, entitled Un2verse, both of which released on July 13. In 2018, Jessi starred on Yo! MTV Raps. The show aired on MTV Asia on July 6. On the same day, she released a single titled “Down”. According to Soompi, AOMG producer Gray took part in producing the track.